Pump plunger



. Jan. 2, 1968 R. L. CHENAULT 3,361,040

PUMP PLUNGER Filed Oct. 6, 1965 M/VE/VTOR 190) L. CHE/VAULT AttorneyUnited States Patent Ofifice 3,361,040 Patented Jan. 2, 1968 3,361,040PUMP PLUNGER Roy L. Chenault, Dallas, Tex., assignor to United StatesSteel Corporation, a corporation of Delaware Filed Oct. 6, 1965, Ser.No. 493,503 5 Claims. (Cl. 92-180) ABSTRACT OF THE DISCLOSURE A plungerfor use in subsurface oil well pumps, The plunger has metal surfaceswhich provide a metal-to-metal seal with a pump barrel and a softpacking between the metal surfaces. One of the metal surfaces is formedon a radially adjustable sleeve to facilitate aligning the parts.

This invention relates to improved plungers for subsurface oil wellpumps and the like.

An object of the invention is to provide improved plungers which combinethe advantages of a closely fitted metal-to-metal seal with those ofsoft self-adjusting packmg.

A further object is to provide improved plnngers which incorporate aself-cleaning feature, whereby flow through the plunger is directed overthe top thereof to prevent sand and other foreign material from settlingand accelerating Wear of both the plunger and pump barrel.

In the drawing:

FIGURE 1 is a half side-elevational, half sectional view of a plungerconstructed in accordance with my invention; and

FIGURE 2 is a similar view showing a modification.

The plunger shown in FIGURE 1 includes a unitary tubular metal bodywhich has a pair of vertically spaced downwardly facing shoulders 12 and13 intermediate its length, and an externally threaded portion 14 at itslower end. I fit soft packing 15, preferably in the form of chevronrings, around the plunger body abutting shoulder 12. I fit a metalsleeve 16 around the plunger body abutting both shoulder 13 and thelower end of the packing 15. I mount a nut 17 and a bushing 18 on thethreaded portion 14 of the plunger body to hold the parts assembled. Theupper face of nut 17 has a circular groove which contains an O-ring 19.The O-ring abuts the lower end of sleeve 16 to afford a seal. Thebushing 18 is designed to carry a conventional valve cage (not shown).Both the sleeve 16 and the upper portion 20 of the body 10 are designedto have a close metal-to-metal fit within a conventional pump barrel 21.The sleeve has clearance with the body 10, as indicated at 22, tofacilitate aligning the sleeve with the upper portion 20 when I insertthe plunger in the pump barrel. The body 10, nut 17 and bushing 18 havea series of wrench flats 23 to facilitate assemblying the parts.

The upper end of the body 10 carries a cage 24 which has threads 25 toreceive a conventional valve rod (not shown). The cage has slots 26 fordelivering fluid from the interior of the plunger to the spacethereabove. These slots are located immediately above the top of theplunger body 10. This arrangement eliminates any settling space abovethe plunger where sand and other foreign material can collect andaccelerate wear on both the plunger and pump barrel.

FIGURE 2 shows a modification in which the upper portion of the plungerbody 10a carries a second removable metal sleeve 27. This sleevefurnishes the metal-tometal contact with the pump barrel in place of thebody itself. The body has an upwardly facing shoulder 28 which the lowerend of sleeve 27 abuts. Cage 24a abuts the upper end of sleeve 27 tohold the parts assembled. I can fit sleeve 27 tightly on the plungerbody, since clearance between sleeve 16 and the body enables the lattersleeve to align itself with sleeve 27. In other respects themodification is similar to FIGURE 1; hence I do not repeat thedescription. The modified construction has a further advantage that itdecreases the cost of replacing the wearing parts, since the plungerbody itself is not exposed to wear against the pump barrel.

Most deep well pumps have all-metal plungers and rely on a closemetal-to-metal fit between the plunger and barrel to furnish a seal.Leakage of fluid past a closely fitted metal-to-metal plunger-and-barrelcombination varies with the cube of the diameter clearance. For example,a plunger of given length with a clearance of 0.003 inch in the barrelhas a leakage rate 27 times that of the same length plunger with aclearance of 0.001 inch. Increasing the plunger length diminishesleakage only in proportion to the first power of the plunger length. Byincluding the soft packing intermediate the areas of metalto-metalcontact, I minimize leaking or eliminate it altogether. The areas ofmetal-to-metal contact also serve to protect the packing from abrasiveparticles of any appreciable size, and therefore prolong its life. Thusthe combination of the two forms of seal affords the advantages of eachand produces a much longer life for both.

The arrangements illustrated are for use in a pump which has astationary barrel and a reciprocating plunger. By merely invertingparts, I can use a similar arrangement in a pump which has a stationaryplunger in a traveling barrel.

While I have shown and described certain preferred embodiments of myinvention, it is apparent that other modifications may arise. Therefore,I do not wish to be limited to the disclosure set forth but only by thescope of the appended claims.

I claim:

1. A pump plunger comprising a tubular body, means on the upper portionof said body providing a surface adapted to form a metal-to-metal sealwithin a pump barrel, said body having a pair of vertically spaceddownwardly facing shoulders intermediate its length, soft packingsurrounding said body and abutting one of said shoulders, a metal sleevesurrounding said body below said packing and abutting both the packingand the other of said shoulders, said sleeve providing a second surfaceadapted to form a metal-to-metal seal within the barrel, a nutthreadedly engaging the lower portion of said body below said sleeve andabutting the lower end of said sleeve, and a sealing ring between saidnut and said sleeve, said sleeve having clearance with the portion ofsaid body which it surrounds to permit relative radial movement be tweensaid sleeve and said body after the nut is fixed on said body andthereby facilitate aligning the two surfaces which form metal-to-metalseals.

2. A plunger as defined in claim 1 in which said means is integral withsaid body.

3. A plunger as defined in claim 1 in which said means is in the form ofa second sleeve removably mounted on said body.

4. A plunger as defined in claim 1 further comprising a cage fixed tothe top of said body, said cage having slots located immediately abovesaid body to eliminate any 5 References Cited UNITED STATES PATENTS 5/1920 MacKenzie 92180 X 4 OBannon 92-180 X Bertrand 92-257 X Eklund92-180 X Whitney 92-180 X Thassy 92'-258 X Hyatt a- 92-258 X Gordon92240 EDGAR W. GEOGHEGAN, Primary Examiner.

MARTIN P. SCHWADRON, Examiner.

G. N. BAUM, Assistant Examiner.

